Explore default BSON serialization

[AngelMunoz]

There's the possibility that we can just serialize known BSON values in the emitted JSON, as the MongoDB Extended Spec shows, we're kind of doing half work for ObjectIds so instead of just emitting the "objectid" we could be emitting { $oid: "objectid" } in the same way we could be doing the same for int64, dates, etc

Ideally I'd like to use the canonical form when possible, but if there's not an option using the relaxed form should be enough

• Date
• Decimal128
• Double
• Int32
• Int64
• ObjectId
• Regular Expression
• Binary
• MinKey
• MaxKey
• Array
• Timestamp

[AngelMunoz]

made some explorations with this and I have the following preview converters

    type ObjectIdConverter() =
        inherit JsonConverter<ObjectId>()

        override _.Read(reader: byref<Utf8JsonReader>, typeToConvert: Type, options: JsonSerializerOptions) =
            ObjectId.Parse(reader.GetString())

        override _.Write(writer: Utf8JsonWriter, value: ObjectId, options: JsonSerializerOptions) =
            writer.WriteStartObject()
            writer.WritePropertyName("$oid")
            writer.WriteStringValue(value.ToString())
            writer.WriteEndObject()

    type DateTimeConverter() =
        inherit JsonConverter<DateTime>()

        override _.Read(reader: byref<Utf8JsonReader>, typeToConvert: Type, options: JsonSerializerOptions) =
            let deserialized =
                JsonSerializer.Deserialize<{| ``$date``: {| ``$numberLong``: string |} |}>(reader.GetString())

            DateTimeOffset
                .FromUnixTimeMilliseconds(deserialized.``$date``.``$numberLong`` |> int64)
                .Date

        override _.Write(writer: Utf8JsonWriter, value: DateTime, options: JsonSerializerOptions) =
            let stringValue =
                DateTimeOffset
                    .op_Implicit(value)
                    .ToUnixTimeMilliseconds()
                |> string

            writer.WriteStartObject()
            writer.WritePropertyName("$date")
            writer.WriteStartObject()
            writer.WritePropertyName("$numberLong")
            writer.WriteStringValue(stringValue)
            writer.WriteEndObject()
            writer.WriteEndObject()

they are producing the following json

{
    "insert":"users",
    "documents":[
        {
            "_id":{
                "$oid":"5fc5b6e4545a4775f7f9bfda"
            },
            "age":29,
            "name":"Peter"
        },
        {
            "_id":{
                "$oid":"5fc5b6e4545a4775f7f9bfdb"
            },
            "age":20,
            "name":"Sandra"
        },
        {
            "age":35,
            "name":"Mike"
        },
        {
            "age":39,
            "name":"Perla"
        },
        {
            "age":1,
            "name":"Updateme"
        },
        {
            "age":50,
            "name":"Deleteme"
        }
    ]
}

{
    "update":"users",
    "updates":[
        {
            "q":{
                "name":"Updateme"
            },
            "u":{
                "age":5,
                "name":"Updated",
                "updatedAt":{
                    "$date":{
                        "$numberLong":"1606792932488"
                    }
                }
            },
            "upsert":false,
            "multi":false
        }
    ]
}

NoSQL booster reads the values and shows them as their intended serialized values

it also allows things like these

find "users" {
        // equivalent to a mongo query filter 
        // { age: { $gt: 10} }
        filter {| updatedAt = {| ``$ne`` = DateTime.Now |} |}
    }

{
    "find":"users",
    "filter":{
        "updatedAt":{
            "$ne":{
                "$date":{
                    "$numberLong":"1606793830175"
                }
            }
        }
    }
}

and seem to work fine

of course there might be some caveats to how to do a propper search but that's out of the scope of this project

[AngelMunoz]

I'm not sure how worth or what are the correct data types in .NET for those so I'll leave them pending, If anyone ever wants them, they are very easy to implement